A math wizard from Bangalore, India, by the name of Shakantula Devi made it to the Guinness Book of Records in 1980 when she mentally multiplied two 13-digit numbers in 28 seconds. This was the arithmetic operation she performed: 7,686,369,774,870 x 2, 465,099,745,779 = 18,947,668,177,995,426,773,730. Since then, Ms. Devi had been routinely beating sophisticated computers right in their own turf. In one such contest, it took her only 50 seconds to get the 23rd root of a 21-digit number, while the computer took more than a minute to perform the same job.

My point in writing about Ms. Deviâs astounding arithmetic powers isnât really to goad lesser mortals like ourselves to try to emulate her feat, nor to shame the arithmetic-challenged among us to improve their basic computing skills, but simply to encourage people to accord more respect to numbers in their English prose. Take note, for instance, that I didnât write the year â1980â in the first paragraph as âThe Year of Our Lord Nineteen Hundred and Eightyâ (as some lawyers are still wont to do even now); that I didnât write â13-digitâ as âthirteen-digitâ; that I did not write â28 secondsâ as âtwenty-eight secondsâ; and that I didnât write â23rdâ as âtwenty-third.â The grammar of numbers and time is not a scienceâtoo many national and cultural variations militate against a universal numbers-writing styleâbut we certainly can minimize unsightly crimes of prose innumeracy by agreeing on a basic numbers stylebook.

Let us begin with two generally accepted rules: (1) numbers from 1 to 10 should be written as words when used in a sentence: âThe customer ordered eight red shirts and five blue ones, but returned three brownsâ; and (2) numbers from 11 upwards in a sentence should be written in numerals: âThe professor discovered to her dismay that 12 of her pupils were absent, and that 546 of the entire student population did not make it to their classes either.â And if perchance the sentence has numbers ranging from 1 to any number higher than 10, the two rules above still hold even if it means mixing figures and spelled-out numbers: âWe counted a total of 800 words in her essay and found ten misspelled words and 17 wrong word choices.â

There are just two notable exceptions to these rules. First, any number that starts a sentence should be written in words: âThirteen is considered an unlucky number by some people.â âFour hundred eighty-two years ago, a Portuguese explorer stumbled on a group of islands on the Pacific and named it the Archipelago of St. Lazarus.â Second, when numbers are used to list a series of items within a sentence, all such numbers should be written as figures (or digits) even for numbers below 11: âThese are the 14 reasons why I wonât live in your city: (1) the traffic is horrible, (2) the overcrowding is simply too much, (3) the cost of living is too high, andâŠ (14) it gets so cold there in winter.â

Many people, of course, after writing out a number in words, indiscriminately repeat them in figures enclosed in parenthesis, as in: âI would like to discuss with you today three (3) aspects of the problem being encountered by four (4) of our regional offices.â Is this correct usage?

Definitely not; this kind of absurd overemphasis literally insults the reader. This should be strictly confined to commercial or legal writing, as in writing checks or in preparing affidavits to make sure that nobody can easily monkey around with the numbers: âPay to Cash: Five Thousand Two Hundred Sixty Pesos Only (PhP5,260.00)â ââŠfor an in consideration of the delivery of Eight Hundred Sixty-Seven (867) pieces of widgets.â

Marking time gives us more latitude in using numbers. We can write, say, â9:00 A.M. (or a.m.)â or ânine oâclock in the morningâ depending on the accuracy we want to convey. But most everybody on the planet is agreed that exact dates should be written in numbers, as in âAugust 24, 1946.â

We have to take up just three more important rules about writing numbers before we close: (1) We should use figures and not spell out numbers immediately before a unit of measure: âa 10-minute wait,â âa 3-3/4 cm. length of tape,â â16 Megahertz on the FM bandâ; (2) We should use figures and not spell out numbers that represent statistical or mathematical functions or formulas: âdivided by 6,â multiplied by 9,â âa ratio of 50:1,â â8% biggerâ or â8 percent biggerâ; and (3) We should use figures and not spell out numbers that represent time, ages, money, sizes, scores, and points on a scale: âat 12 midnight,â â4 years old,â â$9,â â5 cm. x 12 cm.,â â73:69,â and âIntensity 5 on the Richter Scale.â

We use numbers all the time in our lives, so it pays to always do our numbers right.